1. Field of the Invention
The present invention is directed to a computer method and system for performing data and signal communication between devices. More particularly, the invention is directed to such communications which utilize Wireless and wireline networking.
2. Related Art
The popularity of the Internet has made a vast amount of information readily available to anyone with an Internet connection. Internet-enabled electronic mail has become an essential form of business communication. Currently, connections to the Internet are predominantly made with landline access links such as dial-up modems, digital subscriber lines, and cable modems.
These types of connections, although pervasive, offer limited mobility to a user and make the sharing of an Internet connection difficult. For example, many libraries offer Internet access at dedicated computer terminals and some universities provide network access jacks at multiple buildings on their campuses for convenient access by students using laptop computers. Both of these approaches offer a means for accessing the Internet at locations other than one's own landline access link, but both require that one remain stationary at the publicly-provided access point and both require a substantial infrastructure investment on the part of the institution providing the network connection. Since it is not generally possible to have multiple users sharing the same network access jack or dedicated terminal, the institution must provide a separate access point for each patron it wishes to service. Additionally, those institutions offering access jacks to their network, such as universities, typically require that the user have a registered network account before being given access to the network, which further limits the network's accessibility to the public.
Similarly, when a customer visits a service provider site on whose computer network the customer does not have an account, the customer will find it very difficult to gain access to the network, and hence to the Internet, email accounts, and other vital data. Should the customer be fortunate enough to gain access to a network jack, the customer will still be at the mercy of the service provider site network administrator. For security reasons, it is customary for service provider companies to set up their computer networks to deny access to anyone not already present in their access list of registered users.
Thus, mobile access to the Internet is limited by two factors. The first is the physical requirement for a user to maintain a line connection to sparsely located network access jacks. The second is the difficulty in gaining access to a network on which one does not have a registered account. The first of these factors has begun to be overcome by the introduction of wireless data networks, which do not require that a user maintain an access line plugged into a network access jack and thus do not require that the user remain stationary. Additionally, because the network connections are made wirelessly, it is relatively easy for multiple users to connect and disconnect from a network using the same access point. Overcoming the second factor is not so straightforward, and is addressed more fully below.
An example of a currently widely available wireless data network is the low speed personal communication service (PCS) network. The primary access devices of this type of network are cellular telephones with built-in Wireless Application Protocol (WAP) features. These wireless networks operate in a licensed frequency band, are centrally planned, and are built by large telecommunication carriers. Typically, each cell has a large radius of about 2–10 miles and operates at a slow speed of about 19 Kbps. In any given geographical region there are only a handful of telecommunication carriers servicing the area, and each network is proprietary and closed to competing networks. Thus, to some degree one is not free to roam from one network to another. Additionally, their slow speed makes full access to the Internet impractical and such network devices are typically restricted to abridged textual displays.
An emerging new class of wireless data networks offer higher speeds of about 1–11 Mbps. These networks operate in an unlicensed frequency band and are based on emerging wireless communication protocol standards such as IEEE 802.11, Bluetooth and homeRF. A common characteristic of these types of networks is a small cell radius of about 200 feet. The cells are radio or infrared base stations that function as access points to a network. Several of these access points may be distributed in close proximity to each other to expand the overall range of this type of wireless network. An introduction to such networks is disclosed in U.S. Pat. Nos. 5,771,462 and 5,539,824.
Various network configurations may be formed using these types of wireless network devices. FIG. 1 shows multiple computers 11 to 17 equipped with wireless network radio devices characterized by respective antennas 19–25. When computers 11–17 are within close proximity to each other, they can form a type of ad hoc network and communicate among themselves. Absent from this type of ad hoc network, however, is a base station cell that can connect their ad hoc network to a wireline network having landline access to the Internet. Therefore, this type of ad hoc network does not have access to the Internet.
With reference to FIG. 2, in order to access the Internet, one needs to gain access to a network having a router 37 which in turn connects the network to the Internet 35. These types of networks are typically characterized by a server 31 which controls access to various services on the network, including Internet services. Workstations 33 connect to the server 31 by means of various types of hardware cabling media 53. The network may provide wireless access points 41 and 43 to respectively couple computers 47 and 49, which are equipped with wireless communication devices illustrated as antennas, to the hardwired network controlled by server 31.
The access points 41 and 43 establish wireless connections with computers 47 and 49 by means of various communication systems such as radio and infrared waves, and have a hardwired connection to server 31 along cable 53. The function of access points 41 and 43 is to relay communication between server 31 and wireless network computers 47 and 49 respectively, but server 31 still controls what services are provided to computers 47 and 49. Thus, server 31 may deny Internet services to computers 47 and 49. Indeed, server 31 may refuse computers 47 and 49 entry to the network if they do not already have network accounts registered with server 31.
As was stated above, wireless networks have a short range, and so a second access point 45 may be used to function as a repeater between a more distant wireless network computer 51 and access point 43. This is an example of using multiple base station access points 43 and 45 to extend the range of a wireless network.
With reference to FIG. 3, many network layout configurations are known, and server 54 need not be located between a router 55 and the other network nodes 61 to 65. In the network layout of FIG. 3, access point 67 has direct access to router 55, which in turn has access to the Internet 59, but this does not mean that server 54 loses its control over the network. Regardless of the layout, server 54 may still be in charge of authenticating new users and assigning resources. Again, access point 67 is illustrated as a wireless access point due to its convenience in permitting multiple users 61 to 65 easy access to the network, but other hardwired access point connections are likewise typical.
In spite of their convenience, such wireless networks have been prohibitive in the past due to their relatively high costs. Until recently, the components required to implement a wireless network had been costly, but recent developments in technology have begun lowering the price of both the cell base stations and radio devices needed to implement a wireless network. Such wireless networks are now becoming more prevalent in the industry, and there may be a time when many small businesses may operate their own autonomous wireless networks. The size of these autonomous wireless networks could range from a city block, to a small building, to a coffee shop. It would then be possible for a mobile user to always have access to a wireless network by means of a mobile computing device equipped with the proper radio communication devices. Thus, this type of wireless network would overcome the first factor limiting the free and mobile access to the Internet discussed above.
Nonetheless, one is still faced with the second factor mentioned above which restricts mobile access to the Internet. Since most autonomous wireless networks are independent, a mobile user would typically not be given access to a target network unless an access account had been set up ahead of time for the mobile user on the target network. Even if a user had access accounts at multiple wireless networks, the user would have to stop his activities and re-authenticate on a different wireless network every time he moved from one autonomous network to another.
Particularly, when multiple mobile users access a wireless network, there has been no way to test the environment and response by the access point serving those users without an actual deployment. Testing these wireless networks by actually deploying mobile user stations (such as laptops) and APs (access points) and then running tests is cumbersome, time consuming and most importantly, cannot be performed without first building a working version of the system.
FIG. 4 shows the basic architecture 100 of a system the like of which may be deployed in a wireless network. In architecture 100, Ethernet communications are handled by an Ethernet card 105 and wireless Ethernet communications are handled by a wireless Ethernet card 110. These are driven by respective drivers 115 and 120. The Ethernet device driver communicates directly with the core Ethernet circuitry 130, while the wireless Ethernet device driver 120 communicates with the core Ethernet circuitry 130 via an 802.11 Protocol layer 125.
The core Ethernet circuitry 130 is the interface which fetches the packet from Ethernet or wireless Ethernet device driver and queue it for the use of the upper level protocols. The core Ethernet circuitry 130 in turn communicates with both IP services 135 which perform routing, IP packet building, and interfacing to higher-level routines 145 and an Address Resolution Protocol (ARP) routine 140 to perform conversions between IP addresses and physical machine addresses within the computer network. The IP services 135 and ARP routine 140 in turn communicate with the higher-level TCP/UDP (Transport Control Protocol/User Datagram Protocol) and application interfaces 145 to provide high-level functionality to communication routines and end-user applications.
Using the implementation of this example architecture allows the core Ethernet functions 130 to interface with all Ethernet device drivers 115 and 120. The wireless driver 120 also uses the same core Ethernet functions to interface with the upper interface layers 135–145. These features of system 100 are typical of a physical wireless Ethernet and wireline Ethernet capable client such as a laptop. These systems transmit and receive Ethernet packets and Wireless Ethernet packets that have different data frame formats
The Ethernet Frame format is shown in FIG. 5. Here, DA is the destination MAC (6 bytes); SA is the source MAC (6 bytes); Type is the protocol type (2 bytes); Len is the data field length (2 bytes); Data is the frame data; and FCS is the frame checksum (4 bytes).
The 802.11 Data Frame format is shown in FIG. 6. FC is the frame control (2 bytes); DID is the duration ID (2 bytes); AD1 is the Address 1 (6 bytes); AD2 is the Address 2 (6 bytes); AD3 is the Address 3 (6 bytes); Seq is a sequence controller (2 bytes); AD4 is the Address 4 (6 bytes); Frame Body is from zero to 2312 bytes; and FCS is the frame check (4 bytes).
In order to test the connectivity of such systems in a wireless network, such systems must be physically duplicated many times over. Thus, there is a need for a single system which can simulate the environment of multiple clients within a wireless network without actually deploying such a network.